Every year millions of hearing tests are conducted in the U.S. for a variety of reasons, including diagnosis of ear disease, evaluation of communicative function, monitoring effects of noise and ototoxic medications, prospective research studies, and fitting of hearing aids. Although there is a =standard" hearing test method, the rules are vaguely defined and loosely followed. This project is designed to test and refine an automated method for testing hearing sensitivity (AMTAS). AMTAS is designed to achieve similar test results to those obtained by expert audiologists while standardizing the method, eliminating errors, increasing efficiency, and decreasing cost. The method preserves the salient features of routine audiometry while applying well-accepted principles of auditory psychophysics. Contralateral masking is presented to the non-test ear whenever the test signal may be audible in that ear. In addition to automating the sequence and timing of stimuli, the method provides quality indicators that alert the audiologist to potential errors due to patient factors or inappropriate masker levels. In this Phase II project, the prototype developed in Phase I will be tested on a wide range of normal and hearing-impaired subjects in three clinical settings. [unreadable] [unreadable]